User Contributed Notes 1 note

getrusage() reports kernel counters that are updated only once application loses context and a switch to kernel space happens. For example on modern Linux server kernels that would mean that getrusage() calls would return information rounded at 10ms, desktop kernels - at 1ms.

getrusage() isn't usable for micro-measurements at all - and getmicrotime(true) might be much more valuable resource.